WASHINGTON -- It only took a day in the Diocese of Davenport, Iowa, for a team of seasoned former FBI agents to declare defeat. The Roman Catholic Church had sent them as part of a nationwide audit to examine whether the diocese had implemented a new policy to deal with sexual abuse by priests.

But church leaders and priests refused to talk to the auditors without their lawyers present. The former agents left town in frustration.

"That's not a legitimate audit," recalled former FBI counterterrorism specialist William A. Gavin, a Winthrop resident and 28-year bureau veteran.

Gavin's company, which included 50 retired FBI agents, was hired to audit 191 of the 195 Catholic dioceses nationwide and question top church officials about their compliance with the sweeping new policy, which mandates reporting, clear procedures, and effective response to allegations of child sex abuse by clergy.

The former agents confronted a reluctant clerical culture, with many priests unaccustomed to persistent questioning by lay people and still adjusting to the new expectations of accountability that resulted from the clergy sex abuse scandal. While Davenport was the most extreme case, the team of former agents met varying degrees of anxiety and initial resistance as they swept through the dioceses over a four-month period beginning in June.

"The whole concept was foreign for them," Gavin said of the bishops and church officials his team interviewed. "This was the first time the laity had stuck their nose under the clergy. There was a lot of angst."

The collision of cultures between former FBI agents and church officials comes as powerful new bodies like the lay-dominated National Review Board are reshaping the balance of power in the Roman Catholic Church.

Some church officials chafed at auditors' questions, as well as inquiries from a separate group of investigators set to release a report next month examining abuse over a 50-year period, because their very presence signaled the new power of lay groups in how the church is run, said Robert S. Bennett, a member of the Review Board and a former lawyer for President Clinton.

"You can tell this is a new thing for them.," Bennett said. "They're simply going to have to get used to it."

Like many of the former agents who conducted the audit, Gavin is Catholic and served as an altar boy at Immaculate Conception parish in Revere. He attends St. John the Evangelist Church in Winthrop. He capped his long career at the FBI as the number two agent at the bureau's massive New York office, with 2,200 employees. Before leaving the FBI in 1995, Gavin had run the investigation of the first World Trade Center bombing and at headquarters was in charge of auditing his colleagues to make sure they were following the rules.

The Conference of Catholic Bishops had already plucked another former senior FBI official, Kathleen McChesney, to run its new Office of Child and Youth Protection. McChesney, in turn, recruited Gavin to conduct the first audit of the nation's dioceses, a year and a half after the bishops adopted a new policy on dealing with abuse.

The bishops liked Gavin, who founded The Gavin Group Inc., not only for his law enforcement bona fides but for his polished, nonconfrontational manner.

The Worcester diocese was one of the first audited by The Gavin Group.

"We'd be crazy to say we weren't a little bit nervous before the audit because we'd never been through anything like this before," said Ray Delisle, a spokesman for the diocese who was interviewed by the auditors. "We were glad it stayed professional."

Although some bishops expressed initial concern about cooperating with the auditors, Davenport turned out to be the exception. The diocese is facing 10 civil lawsuits alleging abuse by five current and two former priests. Yesterday Davenport church officials referred questions to Rand Wonio, a lawyer representing the diocese.

"We gave them all the paper they asked for," Wonio said of Gavin's auditors. But Wonio's law firm advised the diocese to have lawyers present for the interviews conducted to verify the written documentation submitted.

"The Gavin group didn't want to do it that way," Wonio said. "It was probably a lawyer's excess of caution. We were concerned that some of those people might be witnesses in pending litigation."

That sort of response is familiar to former agents like Gavin and McChesney, who ran white collar crime and internal audits much more fraught with tension than this one.

"They are mature individuals who have been audited themselves within the FBI," McChesney said of Gavin's agents. "They knew what it feels like to be sitting where the bishops are sitting."